I've read a ton of posts on here and the consensus seems to be "for maximum power turn off VDC". I still don't fully understand why this would give more power? Can somebody please explain too me (in layman's terms) why turning the VDC off enhances my performance? If I'm at a stop, go WOT in a straight line, surely the VDC has no effect on the car right? Thanks in advance.

 

The only thing I can think of is wheel spin. When you take off with your right foot down on the flooor, your tires will spin, and this will activate the VDC and SLIP feature, and temporarily slow your car down if the wheels are losing traction. With VDC off, the traction control will still be on, but i'd say about...hmm 50% percent less active(safety feature even with the VDC off, the traction control will still stay on if you really lose it) Thats what I think, i'm sure someone could give a bettter, detailed explanation.

 

bloke,
Look at my runs with VDC off and on. I did better leaving it on. Wheel spin is bad.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

You can do better modulating the power yourself to prevent wheelspin. The VDC system retards it too much once it engages.

 

Ryoken,
I thought this too until I did 8 runs, both directions, correcting for every weather variable possible and every single time I had the VDC on I did better. That was with an auto.

I think the VDC works much like the ABS, except on different axis. Would you be able to modulate your brakes better than the ABS? Seriously, I'm not trying to be sarcastic, rather get to the bottom of this. On dry pavement I made several runs, some with and some without the VDC and consistently, I ran better with the VDC on. With it off, even the very slightest detectable wheel spin cost me a couple tenths of a second. Thoughts on that? Maybe there are differences between VDC on 2003.5 and 2004.5? Maybe diffs between coupe and sedan? I don't know but I can't think of anything else that would have affected my times.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

I think this is a totally different argument if you are driving a 5AT. Those of us with the 6MT will do much better at the track with VDC off. When the system detects wheel spin, it cuts power- during your launch as well as when shifting. Several times Ive had friends in the car when the VDC kicked in when vigorously shifting to 2nd gear, and they laughed at me thinking I missed the gear. Honestly, I do believe I can control the wheelspin better than the computer. A little spin is better than a lot of bogging down.

'04 OB 6MT Coupe, everything but Nav
Awaiting Install
-Polished Vortech with gauges
-Polished Crawford Plenum
-Kinetix Cats

Still wont be as fast as my '04 GSX-R 600

 

I agree with Brittain 100%. Now, I haven't timed myself, but I know it sure feels slower, especially when you hit second gear and the gas cuts off.



2004.5 TB/Willow 6MT Coupe
Aluminum Pedals
BEL RX75 Pro Plus
K&N Hi-Flow

 

I ran with the VDC on the track last month at Sears Point, and I'll never do it again. It would kick-in any time the car drifted (i.e., just when you thought you had the corner set-up just right), and the outside rear wheel slipped. The sensation was of shifting from 2nd to 5th gear. It probably cost me a few seconds each time that it kicked in. Multiply that by 3 times a lap, and I was probably losing at least several seconds per lap.

RainMeister
'04 G35C 6MT, diamond graphite, premium, nav, aero

 

Catatafish: I autocross my car, and the VDC kills my times, in the dry and when it's wet. It really cuts the engine power coming out of the corners and doesn't let the car go.. robbing me of more speed than a little wheelspin would. When I tried it out on a wet track, it o made the car understeer so badly that I plowed past a corner and into the outside cones.. with the VDC off, the ABS system by itself would let the front end actually turn. Once you get accustomed to the car, it's not hard to ease into the power coming out of the corners and keep it from spinning the wheels.

No, I can't modulate my brakes better than ABS. Turning off VDC leaves ABS on. However, some people can hold their brakes right at the threshold without locking the tires, which provides better stopping distances than ABS can. I imagine with some practice, I could too, eventually.

I have an auto. Incidentally, "D" sucks, and "2" is a much better position to run around the autocross track in.

<P ID="edit"><FONT class="small"><EM>Edited by Ryoken on 05/04/04 10:03 AM.</EM></FONT></P>

 

Thanks for the comments ryoken. I see your point in an autocross scenario and probably would agree. But I can't argue with the times I achieved on a straight quarter mile on dry asphalt. By the way, I don't have a "2" on my 2004.5 coupe. I just have "D" or manumatic. Maybe this is a Coupe/Sedan diff. I agree that if you know what you're doing (you obviously do), then VDC off is the way to go if controlling over/understeer is an issue. But I'm not sure I agree yet that on straight 1/4 mile it is of benefit and so far it seems to hurt. I'm going to do tons more runs and maybe what happened to me Sunday was a fluke. Cheers.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

i think just the infiniti website description of the vdc system is self-explainatory when it comes to performance. during driving, if the computer senses any slipping or loss of traction, power is adjusted (reduced, reverted, etc) to prevent loss of control of the car.

you can even test it yourself. try starting at a stop and taking off like wot with and without the vdc on. you will notice quite a difference.

 

Britishbloke I took the advice of some of the boardmembers and left it off at ATCO... I saw at your thread and went home last night and looked at my video from a gracious member who filmed the event and mailed it to me on VHS. In slo mo you can see my wheels spin all the way to 60 feet and this is with a 2.19 and a 14.2 1/4. If the VDC were on I can only assume the power would all but shut off and slow the car to 16 or 17 seconds - of course pavement and the 1000 other variables make most assumptions worthless.

I have only hear of one case where the VDC helped out of 100 that didn't. The other sedans ran high 15s and 16s that day so it may be worth it to see if they ran with it on but I dont know who ran in sedan format other than afropuff...

How can I convert VHS to a windows player file without losing my mind?

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Injen CAI
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk ex-3500 Tweeter Upgrade/Shock Sensor/H-Liner Under Hood

 

One way to convert VHS to Computer video:

1. Buy a USB video capture cable $53
http://www.buy.com/retail/Product_ju...mp&dcaid=15894
OR $70
http://www.x10.com/products/x10_va11a.htm

2. Get free capture software and input signal.
http://www.x10.com/products/xrayvision_software5.htm

get: "XRay Vision Remote Download" which allows recorder to see the video in stream.

OR $70 for cable & software: "Dazzle DVC 80 USB Video Capture/Edit" Item # 20061399 , Style # 029061

http://www.officemax.com/max/solutio...8&moreInfo=yes

SAME $53 at:
http://www.provantage.com/buy-7dzml0...6-shopping.htm

04 Diamond Graphite Sedan - 5AT / sunroof /
Deep Cut Rubber Floor Mats (Chicago Winters) /
PREORDER WINDOWS-UP MOD

 

The descriptions I've seen say that it will brake for minor slips and cut off fuel in major slips or redline.

I think the comparisons must be made holding constant the RPMs at the time of launch. I launched at idle, at 1800, and at 2100. At 2100 I peeled out for about a second. At 1800 it was a split second. At idle it was never. My best time was letting go at 1800. Peeling out is wasted HP. Name of the game is efficient transfer of HP to earth. Everything has a point of diminishing return. I shall experiment with this more, but for now I'm keeping an open mind but am convinced that comparing wheel spin to no wheel spin, the no wheel spin will produce a better time. Question is, at what point of "out of control" does the VDC shut off fuel.

When I ran WOT in manumatic in second gear for a HP reading, I felt what that feels like to have the fuel cut off. That never happened with VDC on when I floored it at 2100 RPM. I felt slight modulation from brakes. This tells me that, within reason, the VDC on may provide benefit up to a point, at which point it will become far too aggressive. I believe that point to be when the fuel is cut off.

Z2G, I did test just that, and my accelerometer showed marked differences. I pulled more Gs with the VDC on. This was in a straight line, on normal pavement, with an automatic, and the fuel did not cut off. Also, I pulled more G's at idle launch or 1800 RPM launch than I did with 2100 RPM launch. In the latter, I just sat and spun for a second. It was my worse time of all my runs.



2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

Catatafish: "2" on the manumatic mode. For '03 sedans, this is a max-gear selector, not a current-gear selector. In 2, the auto tranny shifts freely between 1 and 2 (with no indication of which gear it's actually in) but is locked out of 3, 4 & 5. "5" and "D" are effectively the same thing.

The coupes and '04 sedans have a different behavior.